Jack Frost has not been kind to grapes

A tangle of merlot grapevines below Whitewater Hill Vineyard’s tasting room and winery in Grand Junction may have been damaged by the extreme cold in December. Some growers say they will plant hybrid grape varieties that are more cold-hardy.

Western Colorado’s wine-grape crop faces another blow this year after record-low cold temperatures earlier this month killed vines and grape buds across the valley.

“It’s been really cold and it was very early,” said state viticulturist Horst Caspari at Colorado State University’s Western Colorado Research Center on Orchard Mesa. “Our temperatures (in early December) were 18 to 20 degrees lower than normal.”

Grapevines, as do all plants, need some time to acclimate to cold temperatures – to become cold hardy – before they can resist the coldest parts of winter.

This year, however, some of the late-ripening grape varieties, such as merlot and gewürztraminer, were caught by the early cold.

Only twice since 2009 have valley grape growers seen a full crop.

“Merlot doesn’t like it that cold,” Caspari said. “There are a lot of blocks (of merlot grapes) being pulled out.”

Growers around the valley already are reporting damage to this year’s crop.

“We definitely are going to have some significant damage, it’s been so cold for so long and got cold pretty quickly,” said Nancy Janes at Whitewater Hill Vineyards. “It seems like it’s getting colder faster in the fall and not allowing some grapes to get winter hardy. Other factors also play into that, but we’ve seen a lot early extremely cold events.”

Caspari agreed, saying his record keeping indicates the deep cold has been arriving earlier the past few years.

“On average, the 15th of December is the first day our average low goes below 20, but on the fifth and sixth we were 27.7 degrees below our normal,” Caspari said. “Our normal for that day is 22.5 degrees and we were at minus 5.2.”

The loss of merlot particularly affects most winemakers in the valley, who use the versatile grape both as a single-varietal bottling and for blending with other red grapes.

Merlot “is a backbone grape and, when we first started in 2000, merlot was considered the consistent blue-chip performing red grape,” said Talbott. “And it is, (but) it won’t take the sub-zero stuff.”

That’s what Guy Drew does for his vineyard in McElmo Canyon in southwest Colorado.

“I’ve started to plant more hearty grape varieties that should handle the cold here better,” Drew said. “I’m optimistic that our winter damage isn’t too bad. We’re in a canyon and cold air sinks so there is not much you can do about it.”

In December, temperatures in the canyon dropped to 5 degrees below zero in some pockets, he said.

“At that temperature it gets kind of iffy, there may be damage or there may not be. I’ll be making the rounds to take some samples of buds to see how they are doing.”